1. Field of the Invention
The present invention relates to a phantom device having an internal organ simulating phantom.
2. Description of the Related Art
Among various uses of radiation, medical radiation therapy is used to kill cancer cells or alleviate pain for a patient suffering from cancer by emitting radiation to a tumor and preventing the tumor from growing.
In particular, radiation therapy is very useful when cancer cells remain after surgery and there is a high risk of cancer recurrence, when surgery cannot be practiced, when radiation therapy is more effective than surgery, when a combination of surgery and radiation therapy improves the quality of life for a cancer patient, or when a combination of drug treatment and radiation therapy maximizes anticancer effect.
Meantime, radiation therapy is performed by means of expensive medical equipment called a linear accelerator. Since the linear accelerator cannot only output high-dose-rate X-rays and electron beams but also can finely adjust output energy, it is currently used as standard equipment for radiation therapy.
It is essential to radiation therapy that the linear accelerator outputs radiation of appropriate energy. Since radiation conforming to the grade, size, or depth of a tumor results in maximum treatment effect, it is very important to enable the linear accelerator to produce optimal energy radiation.
As such, before using the linear accelerator, it is necessary to check whether the linear accelerator can operate normally and, in particular, can emit radiation at desired energy levels after radiation dose adjustment. This process, called quality assurance, is performed in hospitals periodically or non-periodically.
Various dosimetric systems are used for quality assurance. In principle, a dosimetric system is located under a radiation emitting unit to receive radiation emitted by the radiation emitting unit, and generates and outputs signals corresponding to the radiation. Since optimal radiation appropriate for a patient's tumor cannot be measured without the dosimetric system, an optimal dose of radiation cannot be delivered to the tumor, thereby reducing therapeutic anticancer effect and even causing medical malpractice in cases of excessive radiation exposure.
Conventional dosimetric systems can measure the dose of radiation while being fixed within a radiation path, but disadvantageously cannot move, for example, in repetitive patterns of internal organs of the human body which move according to respiration.
Accordingly, whether accurate or not, information about radiation dosage is obtained from a fixed target, not from a moving one. Since there is a difference between a dose administered to a moving target and a dose administered to a fixed target, it is somewhat difficult to use this information as data for quality assurance of radiation therapy equipment that is to be used to emit radiation to the target moving according to respiration.
As described above, in order to emit appropriate energy radiation to a moving target in a patient's body, that is, to enable the linear accelerator to deliver an accurate dose of radiation to the moving target, quality assurance should be performed by using a phantom simulating the dynamics of the moving target. However, a device that can precisely move a phantom in desired patterns has not yet been developed.